Skin functions

for example against cold, heat and radiation (especially ultraviolet (UV) radiation), these are so-called physical irritations. We may also have contact with chemical irritations, e. g. at work or in the household. Our skin also works as a buffer against pressure, blows and friction (mechanical irritations). In addition, it prevents the penetration of micro-organisms like e. g. bacteria into the body. And it makes sure that we do not lose too much warmth and humidity.

With a pH value of around 5.5 to 5.7 the skin is slightly acid and forms a protective layer around the body that can fend off foreign germs. The skin also harbours defence cells that react immediately as soon as foreign bodies penetrate. You can see this in the reaction to an insect bite: the place of the bite becomes red, swells and itches. These are defence reactions initiated by the defence cells.

Thus the body avoids overheating by discharging sweat (thermoregulation). A human can sweat out up to 10 litres of liquid in a day. With the sweat, the body also discharges minerals – that’s the reason why sweat is salty. In this way, the skin does not only regulate the body temperature and the water balance within the body, but also has a significant impact on the mineral metabolism of our organism.

The skin allows us to perceive vibrations and pain, but also touch, pressure and temperature. There are different receptors for all these sensations (e. g. temperature and pain).
Regarding temperature and pain, there is one difference: you can get used to warmer temperatures, if the change happens slowly. This is not the case for pain, and it wouldn’t make sense either: pain has an important function as a warning signal, which should not be cut out by habituation.

Human skin usually produces vitamin D as Vitamin D3 (cholecalciferol or shortly calciol) by absorbing UV B light. This vitamin is very important for humans, as it is responsible for the build-up of the bones.

Dissolved substances (liquid and aerogenic) e. g. can penetrate into deeper skin layers alongside the hair follicles. Thus skin creams or drugs in the form of creams or ointments can penetrate the skin and improve the skin condition. In the same way, however, also harmful substances can enter the body.

The skin determines our appearance. So some people have e. g. darker or fairer skin than others or have freckles. And wrinkles and lines appear in the course of the years and form an essential part of our facial expression. We can have laughter lines and worry lines, we can wrinkle our noses and knit our brows. In higher age, wrinkles develop as a cause of skin ageing.
The skin also reveals our feelings. If we feel angry or embarrassed, we may blush, if we get scared, we tend to look bleak. And the famous “goose bumps” show that we feel cold or that something gives us the creeps. With all these signs the skin lets ourselves and the people around us see how we feel.